Electric-resistance element.



UNITED STATES PATENT OFFICE.

GUY M. LAIRD, OF CHICAGO, ILLINOIS, ASSIGNOR OF. ONE-HALF T LEO B. LINCOLN, OF CHICAGO, ILLINOIS.

ELECTRIC-RESISTANCE ELEMENT.

1 7,272. Specification of Letters Patent. Patented Feb, 19, 1918, No Drawing. Application filed May 19, 1916. Serial No. 98,674. To all whom it may concern: chromium resistance material now so largely Be it known that I, GUY M. LAIRD, a citiused. To make the material more ductile zen of the United States, residing at Chlthan it would otherwise be, cobalt may be cago, county of Cook, State of Illinois, have added. While the nickel or nickel and cobalt invented a certain new and useful Improvealloys will ordinarily be preferable, iron, 40 ment in Electric-Resistance Elements, and when alloyed with silicon will give excellent declare the following to be a full, clear, and results, it being necessary of course that the exact description of the same, such as W1 l1 iron be pure so that it will not oxidize under enable others skilled in the art to WhlCh 1t ordinary atmospheric conditions; pure iron pertains to make and use the same. being practically non-oxidizable at ordinary My invention or discovery consists in the temperatures and the addition of the silicon production of a new electrlc resistance elcraising the melting point so that oxidation ment composed of a metal which shall have at high temperatures does not become apprethe property of being particularly low in ciable until a much higher temperature is electric conductivity, have a melting point reached than will be the case with the iron 60 exceeding that of pure copper, and be capaalone. ble of resisting oxidation at all temperatures The amount of silicon employed will vary and under all conditions to which it needs according to the service to which the resistto be subjected, while at the same time ance material is to be put. In some cases possessing characteristics permitting it to the silicon content will amount to only a few be drawn or otherwise worked to form strips, per cent., while in others it may be as high strands or filaments; whereby highly efiias twenty-four per cent. Where the alloy cient and extremely durable resistance eleis of nickel, cobalt and silicon, it may be ments result. stated as a general rule that the nickel con- My invention or discovery consists simply tent should be at least seventy-five per cent. in making an electric resistance element of of the whole. an alloy of one or more of the members of I claim: the nickel group of metals (nickel, cobalt, An electric resistance element formed of and iron) with silicon- The addition of silian alloy of nickel, cobalt and silicon and con to nickel, for example, raises the melting containing at least seventy-five per cent. of point of the latter and also the. temperature nickel.

at which oxidation will take place and at In testimony whereof, I sign this specifithe same time lowers its electric conductivcation.

ity, givlng a resistance element very similar in essentlal characteristics to the nickel- GUY M. LAIRD. 

